The present invention relates to an adjusting arrangement and more particularly, to a drilled hole end adjusting arrangement for a drilling machine or the like mounted on a boom or jib structure, in which arrangement, the positions of the ends of the drilled holes are adjusted so as to be in a plane parallel to a rectangular coordinate plane established immediately in front of working face to be drilled irrespective of the unevenness of such a working face.
Commonly, drilling machines, for example, rock drills or rock borers, are widely employed in mining, tunnel excavation, etc., for drilling rocks to form openings or holes in such rocks so as to enable placing therein of explosives and the like for blasting or for sampling rock cuttings to determine the mineral content of ore. Such a drilling machine is normally supported by an associated boom or jib structure which is mounted on a vehicle such as a truck or crawler and operated, for example, by hydraulic rams for correct positoning of the bit of the drilling machine with respect to the rock or object to be drilled.
The conventional arrangement as described above, however, has a serious disadvantage in that, since the movement of the boom structure is based on particular spherical coordinates or spherical loci different from rectangular coordinates or rectangular loci well suited to human senses, it has been extremely difficult to designate proper positions of such a boom structure in an efficient manner. More specifically, in the conventional arrangement as described above, it is a general practice, for example, as disclosed in U.S. Pat. No. 3,980,142, to set up servo or servo-mechanism by detecting displacement of the hydraulic cylinders for driving the boom structure, and since it is difficult to numerically designate the position of the boom distal end, i.e., the position of the bit of the drilling machine, there has been employed a system known as a reproduction control system (i.e., utilizing the so-called play back method) in which the positioning work is preliminarily effected by manual operation so as to be memorized for subsequent reproduction. The known play back method as described above, however, has such drawbacks that when the positions of the ends of drilled holes are to be adjusted so as to be in a predetermined plane with respect to an uneven working face, it is necessary to memorize the drilling position every time the depth of drilling is altered, and the memorizing operation is complicated and requires considerable time. Moreover, because the programming of the operating machine (i.e. drilling machine) must be by human skill, this not only reduces working efficiency, but tends to be erroneous, and is not capable of numerical designation of the positions.